The inspection of untinted contact lenses is known. Techniques and systems for inspecting untinted contact lenses are disclosed in U.S. Pat. Nos. 6,246,062; 6,154,274; 5,995,213; 5,943,436; 5,828,446; 5,812,254; 5,805,276; 5,748,300; 5,745,230; 5,687,541; 5,675,962; 5,649,410; 5,640,464; 5,578,331; 5,568,715; 5,443,152; 5,528,357; 5,500,732; 4,981,487; 5,244,470; 6,196,683; 4,668,240; 5,824,719; 4,963,159; 4,946,269; 4,872,404; 4,898,695; 5,255,077; 4,634,449; 4,705,370; 4,777,684; 4,733,959; 5,271,874; 4,889,421; 5,055,602; 5,034,166; 4,997,897; 5,116,112; 5,120,121; 5,871,675; 5,938,795; 6,048,371; 6,132,043; 6,322,214; 6,364,934; 6,149,842; 6,096,799; 5,846,457; 5,824,276; 5,792,822; 5,534,038; 5,452,658; 5,292,350; 5,160,463; 6,248,266; 5,151,106; 5,271,874; 5,271,875; 5,466,147; and 6,348,507, all of which are hereby incorporated by reference in their entireties. Additionally methods of tinting contact lenses have been disclosed in the following applications, U.S. patent application Ser. No. 09/745,511 filed Dec. 22, 2000; U.S. patent application Ser. No. 09/792,671 filed Feb. 23, 2001; U.S. patent application Ser. No. 10/027,579 filed Dec. 20, 2001; U.S. patent application Ser. No. 10/165,058 filed Jun. 7, 2002 all of which are hereby incorporated by reference in their entireties.
Before this invention, automated inspection techniques had not been used for inspecting the application of tint to a tinted contact lens. The application of the tint was either not inspected or it was done manually, by operators who visually inspect each lens to determine if the tint contains any irregularities, and if the layers of tint are concentric to the edge of the mold. If any irregularity or flaw in the tint was found and it made the lens unsuitable for consumer use, the lens was identified so that it was not subsequently sold to a consumer.
This prior art inspection system is subject to human error. Additionally, a manual inspection step would likely be located after the lens has gone through most, if not all, of the manufacturing steps. An automated inspection system that could be inserted at any convenient location within the manufacturing line would be desirable to avoid fully processing lenses that will ultimately be rejected. Additionally, if the inspection system is immediately after the application of the colorant to a lens or to a lens mold, then if there are a high number of rejects, a problem within the area of the machine where the colorants are applied can be immediately addressed, and not discovered much later during production after many more lenses have been made having a defect in the colorant.
This invention provides a method and system that inspects the tint and/or printed patterns on a contact lens or mold for molding a contact lens therein. The method and system finds defects including voids in the colorant, excess colorant, and incorrect position of the colorant and/or pattern(s) of the colorant with respect to the center and/or edges of the ophthalmic products, e.g. mold or contact lens or other colorant layers.
One benefit of this invention is that the inspection does not have to be done on finished lenses, but can be done immediately after the colorant is added to the mold or lens. This provides immediate feedback to the machine to reject for various defects and allows the machine operator to react quickly if numerous defects in the colorant are being made. An additional benefit is that because defects are difficult to define, standardize and learn, human inspection often gave inconsistent results, whereas the automated system gives more consistent results. This invention also comprises the system described herein for performing the method of this invention.